The Amazing Race -- how did Phelps do it?

I now have two contenders for the "Best Event I've Seen at the Olympics In Person" award.

The first was the men's 4x100 relay, when American Jason Lezak chased down France's stud swimmer Alain Bernard in the final five meters.

The second just happened Saturday morning (Beijing time). Michael Phelps, who was seventh out of eight halfway through the 100 butterfly, somehow won the race in the final centimeter for his seventh gold medal. Phelps beat Serbia's Milorad Cavic by the closest margin possible in swimming -- 1/100th of a second, 50.58 to 50.59 seconds.

I was watching the race live at the Water Cube, sitting with another reporter, and I thought Phelps had lost even after both swimmers touched. My angle wasn't the greatest, but he was clearly behind until the final stroke. Then Cavic tried to glide in and Phelps windmilled his arms one more time -- a short and choppy half-stroke -- that propelled him to the victory.

The Serbs questioned the result and (sort of) protested, but swimming officials reviewed the results by video, frame by frame, slicing it down into 1/10,000th of a second increments. And Phelps still won, every time. "I'm completely shocked," he said afterward.

Cavic said he believed he would beat Phelps if they raced again -- and it's quite possible he would -- but he didn't this time. Phelps said he chose the half-stroke because he knew he needed to rally -- it was something of a mark of desperation.

And it was unbelievable. The eighth gold medal is now a formality for Phelps unless the U.S. false-starts in the 4x100 medley relay.